Adjustable chair.



H. S. ALLISON.

ADJUSTABLE CHAIR.

APPLICATION FILED AUG.14, 1912.

I Patented Sept. 22, 1914.

3 SHEETSSHEBT l.

x awvo/wlloz Z277 -51 42/23011 H. S. ALLISON.

ADJUSTABLE CHAIR.

APPLIOATION FILED AUG. 14, 1912.

Patented Spt.22,1914.

3 SHEETS-SHEET 2.

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H. S. ALLISON.

ADJUSTABLE CHAIR.

APPLIOATION FILED AUG.14, 1912.

Patented Sept. 22, 1914.

3 SHBETS-SHEET 3.

51mm 6. j/Zzls'ar UNITED STATES PATENT oFFIcE.

HARRY S. ALLISON, or INDIANAPOLIS. INDIANA, ASSIGNOR 'ro W. n. ALLISON, or

' INDIANAPOLIS, INDIANA.

ADJUSTABLE CHAIR.

ti'nes-'ccnform to the natural position; of

' the body of the occupant without necessitatmg any movement on his part, and shall at all times be in balance. Principally,it is desired to obviate the necessity for the occupants pushing himself upward and backward as the chairs back is tilted to the rear, in order to maintain his head'incomfortable position on the headrest.

The accompanying drawings illustrate my invention.

Figured is a side elevation of a chair embodying my invention; Fig. 2 is a partial rear elevation, on a larger scale, of the chair-back; Fig. 3 is a section on the line 3-3 of Fi 2; Fig. 4 is a vertical longitudinal section through the chair, some parts being removed or broken away; Fig. 5 is a section on the line 55' of Fig. 6; Fig. 6 is a section on the line 66 of Fig. 4; Fig. 7 is a partial section on the line 77 of Fig. 6; and Fig. '8 is a partial side elevation showing the seat tilted In the pedestal 10 is mounted a post 11, which may be raised and lowered in the pedestal in any suitable manner. 'A saddle 12 is pivotally mounted on the post 11 substantially at the top of the latter, and has two downwardly projecting arms 12 which at their lower ends bend outward and support the frame 13. This saddle construction allows the pivot for tilting the seat to be close up under the seat, thus permitting a lower position of the seat desired in. special nose and throat work, and at the same time affords pockets between the arms 12 and the frame 13 for the passage of various operating bars. The saddle 12 and frame 13 may be locked in desired position in any usual manner.

A seat frame 15, which may be provided with a removable seat 16 having adjustable arms 17, is hung within the frame 13 by links 18 at the front and links 19 at the Specification. of Letters Patent. Y Application filed August 14, 1912.

Patented Sept. 22, 1914. Serial no. 715,011.

back, the links- 19 projecting upwardly and being integrally connected to form a back frame 19.

links 18 and 19 are connected by links 20,

so that they will swing together and keep the seat frame 15 always substantially parallel to the frame 13'.

' A leg frame 25 ispivoted to the front end i of the seat frame 13, and to the lower end of the leg frame is pivoted a foot piece 26. A. link. 27 connects-each side of this front piece, at the back, to a point on the seat frame 13, so that as the leg frame is tilted relatively to the seat frame the foot piece is oppositely tilted relatively to the leg frame. The tilting of the leg frame relatively to the seat is obtained by a pair of connected levers 28 pivoted to the seat frame 15 and Corresponding front and rear proyecting on both sides of the pivots, the

upper ends of such arms being connected by links 29 to the frame 13 and the lower ends being provided with pins for engaging teeth on the lower sides of a pair of interconnectedbars 3O pivoted to the leg frame 25. Thus the leg frame may be adjusted relatively to the seat frame, and swings relatively thereto as the latter is swung about the pivoted centers of the links 18 and 19. Both the links 20 and 29 and the bars 30 extend through or into the pockets between the arms 12' of the saddle and the frame 13.

A back 35, carrying at its upper end a removable and adjustable head piece 36, is longitudinally slidably mounted on the back frame formed by the upward extension 19 of" the links 19. A rack 37 is longitudinally adjustably mounted on the rear of the back 35, to which it ma be locked in any position by a hand camping wheel 37" and meshes with a pinion 38 mounted. on the back frame 19. This pinion also meshes, opposite the rack 37, with a rack 39 carried by the clampingrod 40 of a bracing frame 41 pivoted to the frame 13 to the rear of the pivoted points of the links 19. The frames 19 and -11 can be clamped together'by the proper manipulation of a clamping handle 4-2 on the clamping rod 40. W'hen. not clamped together, and then only the back may be tilted relatively to the frame 13, the seat frame 15 and the leg frame 25 at the same time being swung about their pivotal axes. Thus as the back is swung backward, both the seat frame and the leg frame are swung forward and upward, maintaining the chair in balance. As the back swings backward, the back frame 19 moves relatively to the end of the bracing frame 41, the latter moving upwardly along theback frame. As the rack 39 moves upward with the bracing frame 41, the pinion 38 is turned counter-clockwise (Fig. 2) to move the rack 37, and the back 35 with it, downward along the back frame 19. ment of the back frame accommodates the back 35 and the head rest 36 to the occupant of the chair without the necessity for such occupant to readjust himself in the chair or for the operator to readjust the head rest. As the back is swung upward and forward, the reverse action takes place, the chair being maintained both in balance and in proper adjustment for the occupant.

. back frame angularl This downward m0ve-' I claim as my invention:

An adjustable chair, comprising a seat, a adjustable relatively to said seat, a back slldably mounted on said back frame, a bracin frame engaging said back frame at an angle, a pinion carried by said back frame, and two racks carried by 'said back and said bracing frame respectively and meshing with said pinion on opposite sides of the latter.

In witness whereof, I have hereunto set myhand and seal at Indianapolis, Indiana, this 6th day of August, A. D. one thousand nine hundred and twelve.

, HARRY s ALLISON. [1 5.]

Witnesses:

HENRY H. DA V111, ALICE M. Cox. 

